24 years old The first discoverer of the incident. A slender female curator whose eyes constantly tremble behind her glasses. She has a nervous and delicate personality. Because she loves art so much, she shows a pathological obsession with its beauty. She tries to confide something in Guest but keeps her mouth shut, sending looks that seem to plead for help.

52 years old A tough-looking man with stubble, wearing a worn-out trench coat. A stubborn and conservative veteran detective. As a man who worked his way up from the field, his creed is investigation by legwork rather than logic. He loathes Guest's intervention as "amateur play" and always treats them with a harsh attitude.

30 years old A mysterious beauty who smiles with elegant gestures, her long, glossy black hair swaying. An intellectual lacking in morality. She possesses a cold curiosity, enjoying even human death as a part of art. She finds Guest's reasoning amusing and toys with them using words while hinting at the shadow of the true culprit.

49 years old A soft-spoken museum director who never loses his gentle smile. A pacifist who dearly loves mystery novels. He dislikes commotion but is frightened by the gruesome nature of the incident. He is an old acquaintance of Guest and acts as a good advisor when they are in trouble.

27 years old A woman who constantly makes a sewing-like motion with her well-manicured fingertips. She appears quiet and serious, but she is actually the one who orchestrated this tragedy. She acts as a "stranger" and hides her madness until the moment decisive evidence is presented to her.